


In the Lab

by in2sin



Category: Magic Kaito, 名探偵コナン | Detective Conan | Case Closed
Genre: Anal Fingering, Anal Sex, Blow Jobs, Established Relationship, Lab Sex, M/M, Multiple Orgasms, My First Smut, Plot What Plot/Porn Without Plot
Language: English
Status: Completed
Published: 2019-03-08
Updated: 2019-03-08
Packaged: 2019-11-13 19:52:02
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,340
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18037808
Author URL: https://archiveofourown.org/users/in2sin/pseuds/in2sin
Summary: Haibara won’t be happy if she finds out what he’s doing in her lab while she’s away.





	In the Lab

**Author's Note:**

> Hiya guys, this is my first work here so I hope you will let me know how I do. This was a writing prompt I got from a book of them to practice my writing so if any of the works I used seem strange that's why. Hopefully, you mostly won't notice. Anywho, enjoy!

Summary: Haibara won’t be happy if she finds out what he’s doing in her lab while she’s away.

Shinichi slammed into the cold metal table, but he didn’t really care as intense pleasure and heat radiated into him from the front. He moaned greedily for more as something was knocked onto the floor.

Hopefully nothing breakable. If he got caught doing this here, the consequences would be severe.

~

“This temporary antidote should hold up for the next 72 hours. If it manages to do so, then we’ll know I’m getting closer to the goal.” Ai said as she placed a small white and blue tablet into Conan’s hand.

“So we just observe the timeframe and if anything feels off as per usual.”

“Of course. Now I won’t be here to observe you as usual so take notes about your eating habits, temperature, blood pressure, and anything that you feel is noteworthy.” Ai ticked off.

He had come to understand what Ai felt was noteworthy. Wait. “You won’t be here to observe?”

“Finally caught that did you Meitantei? No, I won’t be. I’m going with Hakase to the convention where he’s meeting his friend. His friend happens to be a pharmaceutical scientist, and I’m interested in some of the research papers that he’s due to present. Plus I don’t want to be stuck here with you for a long weekend while you pout about having to stay hidden.” Ai responded in that bland, uninterested tone of hers. 

“Since when have you been interested in pharmaceutical research? You’re a microbiologist after all.” He grumbled.

“Since it might help save your sorry hide.”

She and Hakase had packed up and headed out shortly after his transformation and left him in the empty house all on his own. He usually didn’t mind being on his own; however, knowing he couldn’t do anything but be on his own seem to be what was bothering him. He had been ditched. So, feeling bored and slightly annoyed he had done something…unwise.

~

“Yo,” was the greeting after the second ring.

Shinichi pulled the phone away from his ear to stare at the screen. What on earth had possessed him to seriously make this phone call? “Hey, what are you up to?”

There was a brief pause before the teasing reply came. “That’s not the voice I had expected. Seems someone has been taking their Flintsone’s recently.”

Shinichi blushed at the teasing. “Oh, shut up. Since we have a holiday coming up, it seemed a good time to do an experiment weekend.”

“Ho~ and you decided to give me a call? How sweet of you Meitantei.” He could practically hear the shark grin in the other male’s voice.

Face flaming now he blurted out the truth. “I got abandoned and was bored! So I decided you could entertain me for a little bit, idiot.”

“Abandoned, you say?” He asked sounding almost preoccupied.

“Hakase and the devil went to a scientific convention for the weekend. Which I obviously wasn’t invited to due to my current…stature.” 

“They’re gone the whole weekend?” Was the next question and the sound of a crash in the background.

“Yeah, and I didn’t plan on being by myself and able to read. Ai never seems to want to leave me to the task when she’s around, so I didn’t bring enough reading material with me. And of course, I can’t leave the house.” Shinichi huffed.

“Sounds like you need rescuing! And a gentleman never leaves a damsel in distress.” Shinichi sputtered a being referred to as a damsel. “Kaito to the rescue.”

“Wai-,“ the line went silent, and Shinichi glanced at the phone in time to see the phone flash call ended one last time. “What have I done.”

He liked the thief well enough. They had become friends after one too many instances of KID having to get involved with the Black Org and help him. After one incident KID had asked what he was involved with that caused such dangerous situations, and Shinichi had felt he owed the thief the truth at least. He had been surprised when KID had come back with a secret of his own. A week later Kuroba Kaito had shown up to pick him up for school.  
They had switched from rivals to friends, to something more rather quickly and he enjoyed just being around Kaito. But even so, that didn’t mean it hadn’t been unwise to call him up so he could invite himself over for the weekend. Shinichi sighed and went to turn on the news to have something to do.

 

~

It was three hours later when Shinichi wondered downstairs into Ai’s lab. Kaito hadn’t shown up, and Shinichi was half hoping that he had been distracted by something he had to do and wouldn’t make it today. The trouble the idiot might get up to trying to “rescue” him from boredom was untold. He had decided to check and see if Ai had any temporary antidotes hidden anywhere in case of emergencies, this one was holding up well almost 48 hours later. He knew that Ai didn’t think he needed them or would abuse their use, but there were times when they could seriously come in handy.

He was straightening from checking a bottom drawer and slammed back into something warm and solid — then strong arms where banding around his waist.

“Hey there Meitantei,” the words were a husky whisper right next to his ear causing him to shiver.

“I didn’t hear the front door close,” Shinichi replied.

“Of course not,” The thief said in that gratingly sing-song way of his. “No one’s supposed to know you’re here. I couldn’t risk someone seeing you when you came to answer the door or getting suspicious if it seemed like someone was breaking in the front door.”

“So you broke in a window instead? Like that’s less conspicuous.” Shinichi snorted.

“It is when you use the second-floor window. You would be surprised by how few times people look up. Especially at the back side of someone else’s house. And it’s the easiest way to go unseen if you’re no afraid of heights.” Kaito explained as he ran his fingers lightly along Shinichi’s sides.

Shinichi shook his head. He absolutely wouldn’t be surprised by that. Too many murderers would have escaped custody if it weren’t for the fact that Shinichi was one of the few people who did look up.

“Now, how about I help you with your boredom problem, hm?” That was accompanied by a brief lick to his earlobe, leaving little doubt in his mind of how Kaito was planning to help. He shuddered as that sinfully skilled mouth moved down to his neck.

“We shouldn’t here. If-“ the statement was cut off with a groan as the thief began to suck on that spot in his neck. The one that seemed so much more sensitive than any other part and allowed the man to cause the recently reawakened hormones in his body to flare up with a vengeance and have his sanity stolen away.

~

That was how Kaito had been able to persuade him into his current position. The edge of a work table, in Ai’s lab, digging into his ass with his shirt tossed somewhere and rational thought a far distant memory.

Kaito pulled back from the deep bruising kiss and licked those sensual lips, as if Shinichi was a chocolate buffet all for him, then began trailing kisses down Shinichi’s body. It was clear the thief wanted to linger on his collarbone area, probably leave a mark or two but resisted and trailed down to one nipple. He never left marks because they would seem strange when he turned back into Conan.

His hands found their way to the thief’s messy hair as he began to lick teasing circles around the sensitive straining bud. He could only groan helplessly as the man took it into his mouth nipping then soothing the ache with quick firm licks. Kaito took his time torturing that one before moving on to the other that he had been teasing with his fingers. He arched into the delicious sensation Kaito was inflicting upon his hypersensitive body.

Shinichi was so lost in the pleasure that he hadn’t noticed those swift hands working his jeans and boxers off him until he felt the cold air from the lab on his cock. He shivered as much from the cold air as from the filthy look on Kaito’s face as he licked lower on his body.

Shinichi’s eyes rolled back in his head as the warm wet heat of Kaito’s mouth engulfed the head of his cock. The wicked thief began to suck and teasing lick only the tip driving him wild. He thrust his hips trying to get him to take more, but firm callous hands landed on his hips holding him in place. He groaned in desperate frustration causing the other man to chuckle around him. The vibrations sent a zing of pleasure racing through him.

“Ah, Kaito,” Shinichi groaned as the thief suddenly swallowed his length. The suction was perfect, the pressure an exquisite torment, and the pleasure was blistering. When Kaito began fondling his balls, he pulled on the messy hair that he hadn’t remembered fisting. He tried to ease his hold so as not to tear free any of the silky strands. But when that wicked tongue began swirling around the head of his cock in earnest, he forgot everything as blinding white-hot pleasure exploded. He threw back his head with a ragged groan as he came convulsively down the other man’s throat.

Kaito drank him down and continued to suck lightly, making sure to get every drop. Shinichi twitched from the too intense sensation. His eyes flew open, and he let out a squeak as he was lifted onto the metal table. He fell back still reeling from that overwhelming orgasm; the first one always hit him hard. The cold metal was a stark contrast to his heated skin. He barely heard a rustle of clothes over his panting breath. Next thing Shinichi knew the other man was above him. His hair had gone from messy bed head to sinfully tousled. One was innocent the other erotic. It caused a shiver to run done his spine. 

“Ready for more already, Metantei?” Kaito smirked down at him. Shinichi could feel the blush burn down his chest.

“Shut up, idiot!” He grumbled and pulled that smug mouth down for a fierce kiss. The sad thing was that it was true. Growing back into himself usually left his hormones high and his refractory period low. Since he was typically embroiled in one mystery or another when It happened, it was easier to ignore, but experiment weekends were a different story. 

Kaito returned the kiss with equal passion. As his weight settled on him, Shinichi was reminded of the fact that the thief still had all his clothes on. He broke the kiss with a scowl as he reached for the bottom of the other’s shirt and pulled it over his head. Shinichi’s brain short-circuited for a moment as lust consumed his minded as he looked over the leanly muscled grace of his companion. His hands seem to have a mind of their own as they started kneading Kaito’s shoulders and back and moving down. A shiver raked Kaito’s body as he basically molested him. Shinichi’s brain finally kicked back into gear, and he began working on Kaito’s belt as he nibbled on Kaito’s bottom lip.

“It amazes me how naughty you can be,” Kaito gasped out as Shinichi attacked his neck, definitely leaving marks behind.

Shinichi ignored the comment as he pushed down the other man’s pants and boxers and palmed the impressive erection. Kaito tensed above him as he wrapped his fingers around the shaft and thumbed the head. A shudder ran through Kaito as he began to stroke him firmly, rubbing his thumb across the head on every upstroke. Shinichi smiled as Kaito hung his head. It meant the thief couldn’t control his expression as much as he usually could, so was hiding it instead. He didn’t mind it, for Kaito, his poker face was an automatic defense and wasn’t him really trying to hide how he felt from Shinichi. It just meant interpreting when he truly enjoyed something was slightly different. Shinichi was very observant and a quick study. He began twisting his hand as he stroked.

“Metantei…you’re going to want to stop…that if you want to get…to the main course.” Kaito said in a breathy tone. Shinichi smirked at the raw quality of his partner's voice but continued, albeit with a slower pace to tease him a bit. It was only fair since Kaito keep him so riled the whole time.

The thief’s hand slowly trailed down his body again causing him to arch into the touch as slender fingers briefly wrapped around his twitching, and rapidly hardening, cock. He gasped as Kaito stroked him a few times before moving even further. Shinichi tensed as those fingers reached his entrance. There had been no warning as the warm, rough fingers suddenly became cool and slick. He was undoubtedly distracted enough for the magician to get away with the simple sleight of hand trick. He became even more so as one of those fingers began to circle and prob.

Kaito was teasing him back as he put enough pressure for his finger to briefly breach his entrance then pull it back out. Shinichi began to squirm, and his hand stroking the magician started to lose its rhythm even more. When the second finger entered and began scissoring his hand stopped moving altogether. The fingers inside him continued moving, curling every so often, once again trying to pull his sanity apart. The third finger had his hand dropping away from Kaito to scramble at the table beneath him as he began to brush against his prostate.

“Ah God, please Kaito…Now! Inside now,” Shinichi begged.

Kaito’s fingers disappeared from his body, and he almost whimpered at the lost. He made quick work of removing his pants and boxers the rest of the way and lubing up before moving back over Shinichi. His legs were placed over the thief’s shoulders, and he could feel the presses of something hard and thick at his twitching entrance.

Kaito paused there to give him the chance to change his mind. When he nodded that he was ready Kaito slowly began to push inside him, and the pressure was both painful and satisfying. He tried to relax, to keep himself from tensing or apply pressure with his legs to slow him down but it kept happening anyway. Kaito understood and stopped whenever he pushed back to wait for him to adjust before moving again. When Kaito finally bottomed out, he stilled again to let Shinichi adjust to the fullness.

The rhythm started slow, like Kaito was testing if he was ready, before picking up speed and force. Shinichi’s eyes slipped shut as the sinfully delicious pleasure dancing across his nerves. A sudden hard thrust had his eyes snapping open and a moan falling from his lips. That one had been at just a slightly different angle and had hit his prostate, sending an intense wave of pleasure through him. The smirk on his companion’s face practically screamed ‘paying attention now?’ He wanted to scowl but he was becoming a panting, moaning mess and he just couldn’t.

The pace now was brutal, due to the near constant hitting of his prostate, and his nails sank into the thief’s back as he held on for the ride. He was moaning and saying nonsensical things that he could hardly register over the ever mounting pleasure. He could feel it began to build low in his stomach and opened his eyes to look into Kaito’s. Those indigo eyes were looked on him with such intensity even as the furrow to his brows and his mouth open in a pant said he was losing himself in the pleasure as well. He still watches Shinichi with that level of concentration that made it seem like he was seeing deep into him. Kaito flashed him a grin with that look before reaching down to stroke him at the same time. A few quick strokes were all the push he needed.

Shinichi cried out, his voice coming out broken due to all the previous moaning, as he came so hard his vision darkened. But not being able to see just made the sound of Kaito groaning hit him all the harder and sent another spasm through him. He loved that sound. Because it meant that Kaito had finally lost control and his poker face was falling. He was so calm, relaxed, and contain most of the time that he didn’t see it fall entirely away often. Usually, only when they were like this, it twisted something inside of him.

Kaito pressed his body more fully against his and bit lightly into his shoulder as he keeps thrusting, with an increasingly erratic rhythm, until he too came. Groaning in his ear as warmth filled Shinichi in delicious waves.

~

“Where’s my shoe?” Shinichi grumbled as he tugged on his shirt to straighten it out. Now that his hormones had calmed he was feeling increasingly more uncomfortable with where this had all happened and was trying to remove them quickly and any evidence of them from the area. If Haibara found out about this, he would be digging a trench for her to hide his body in.

“It’s slightly under the computer desk,” Kaito said in a cheerful tone.

Shinichi scowled at him. “She’ll kill you too. You know that, right?”

He was treated to a look of false innocence. “Me? But I’m just an innocent bystander. Should I be murdered for coming to rescue my favorite detective?”

“Bystander my ass,” Shinichi grumbled as he bent over to reach one of the house shoes he’d worn down here for the search.

“Do you see my sock over there?”

“No,” Shinichi said flatly.

“Aww, come on Tantei-kun don’t be so sour, you had fun, right?” Kaito beamed at him.

The blush was instantaneous, and he could feel it burning all the way to the tips of his ears. Before he could get distracted by the memory of their ‘fun time’ the telephone rang. He glanced at the unit on the desk and noticed Haibara’s number. He quickly made his way upstairs to answer so she wouldn’t hear the sound difference between the basement and the wide open area of upstairs.

“Hey Haibara,” he said when he picked up.

“It’s still holding up then. Good. Have you noticed any side effects or issues?”

He thought of his hormones and shook his head. That was not a noteworthy side effect to Haibara and not one he particularly felt like talking about with her if he could avoid it. “Nothing noteworthy.”

She gave a small ‘hmm’ of approval before speaking again. “Hakase and I are on our way back. We should be there in about two hours, anything you want us to pick up along the way.”

He tried to stay calm. “No, not really. What happened? I thought you weren't supposed to be back until tomorrow evening.”

There was a pause on the other end that had him panicking for a moment, thinking he had given something away with his tone. “Hakase’s friend had an emergency come up and had to leave. So, we saw no reason to stick around any longer.”

“Guess I’ll see you guys soon then,” he said casually.

He gave a sound of agreement then hung up. He turned back to the basement door to see Kaito standing there. “Change of plans then?”

“Yeah. Please tell me you found your sock,” Shinichi said with a hint of pleading in his voice. When Kaito shook his head in the negative Shinichi dropped his head into his hands. “I’m so dead.”

~

**Author's Note:**

> 7 pages later on this “short” writing prompt, I hope you all liked this little bit of smut. Feel free to comment and let me know if you liked it, if there were errors that I need to fix, or if my writing style was confusing or anything like that. I’m practicing my writing with random writing prompts so any feedback would be great.


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